Known photographic processes for obtaining a color positive image by using dye developers, i.e., compounds having a hydroquinone type developing agent moiety and a dye moiety in their molecule, include the wet development process as disclosed in U.S. Pat. Nos. 2,983,606, 3,415,644, and 3,594,164, etc., and the heat development process as disclosed in Japanese Patent Application (OPI) No. 165054/84 (the term "OPI" as used herein means a "published unexamined patent application"). That is, when a light-sensitive element which has been imagewise exposed is developed with a dye developer, the dye developer is immobilized in the developed areas. The dye developer which remains mobile is then transferred to an image-receiving element to thereby form a positive image. It is believed that the dye developer is immobilized through formation of an oxidized product upon exposure to light and, thus, substantially inhibited from transferring.
However, the above-described color photographic process using the dye developer is sometimes unsatisfactory in inhibition of transfer. As a result, the highlight portion that should become white may have higher density than desired, i.e., a higher minimum density, thus undesirable poor color separation may occur.
U.S. Pat. No. 3,173,786 discloses that transfer of an oxidized product of a dye developer can be suppressed by using an onium compound. However, it has been found that the onium compound not only causes desensitization of a light-sensitive element, but also reduces image density, particularly in a process using heat development.